Extracting tool



Sept. 15, 1964 REETz 3,148,566

EXTRACTING TOOL Filed Jan. 8, 1963 Qzv/ [2 11 g .3 f f a m VENTOR.

ATTORNEY United States Patent 3,148,566 EXTRACTING TOOL Ted F. Reetz, 314 Virginia, Monroe, Iowa Filed Jan. 8, 1963, Ser. No. 250,040 1 Claim. (CI. 81-71) This invention relates to a tool for extracting a threaded male member from an associated threaded female member and more particularly to a tool for backing off damaged and broken off pieces of pipe, and pipe nipples, or to remove the remaining portions of screws and studs which have been broken off close to the threaded female member.

It is the object of the present invention to provide an improved tool which includes a tapered working section having a polygonal cross section and is adapted to positively engage a threaded male member and to apply thereto a torque for removal of the threaded male member from an associated threaded female member.

Another object of the invention is to provide a tool, for removing broken studs provided with a center bore, which is self-centering and automatically maintains itself in alignment with the axis of the bore as the tool is driven into the same.

A further object of the invention is to provide a tool adapted to be driven into a center bore of a stud to positively engage the side wall of the bore and which, when a torque turning force is applied thereto, tends to move inwardly of the stud into more positive engagement therewith.

An additional object of the invention is to provide a rugged tool for removing broken studs which is relatively simple and economical in construction and reliable and efficient in use.

The exact nature of the invention as well as other objects and advantages thereof will be readily apparent from the consideration of the following specification relating to the annexed drawing in which:

FIG. 1 is a foreshortened perspective view of the tool of the invention;

FIG. 2 is a foreshortened enlarged plan view of the tool shown in FIG. 1;

FIG. 3 is a foreshortened enlarged side elevation view of the tool shown in FIG. 1;

FIG. 4 is an enlarged end view of the working section of the tool looking toward the right as viewed in FIG. 2;

FIG. 5 is an enlarged sectional detail view illustrating the tool shown in FIG. 1 in assembled relation with a broken stud provided with a center bore; and

FIG. 6 is a sectional view taken along the line 55 of FIG. 5.

Referring to the drawing, there is shown in FIGS. 1 to 4, the extracting tool 10 of the invention. The tool 10 is formed from a linearly elongated metal body 11 of material commonly referred to as tool steel. The body 11 is divided into a handle section 12 and a working section 13.

The handle section 12 comprises the upper part of the body 11 and is non-circular in cross section, preferably square and is adapted to receive a wrench or socket handle for rotating the tool. The end 14 of the handle section 12 is flat and forms an impact head for receiving blows from a hammer.

The working section 13 comprises the lower part of the body 11 and has a non-circular cross section which has a trapezoidal shape corresponding to an oblong parallelogram having unequal adjacent included angles. The actuate angles of the parallelogram are approximately 60 and the obtuse angles are approximately 120, as best appears in FIG. 6.

As shown in FIG. 3, the working section 13 has flat top and bottom surfaces 16 and 17. Each surface 16 and 17 has a uniform taper of between 3 to 8 with re- "ice spect to the longitudinal axis of the body 11 and converges toward the working section end 18 which has a chisel-shaped edge 20. The opposite sides 19 and 21 of the working section 13 are flat and each has a uniform taper of between 2 to 5 with respect to the longitudinal axis of the body 11. The sides 19 and 21 converge toward the working section end 18 and terminate in the chisel point 20. The top and bottom surfaces 16 and 17 join the opposite sides 19 and 21 to form oppositely directed knife edges 22 and 23 which taper uniformly and inwardly toward the working section end 18 of the tool.

As shown in FIGS. 5 and 6, the tool 10 is used to remove a broken threaded male member 24, such as a broken off stud, or pipe section, from a threaded female member 26 having a threaded bore 27.

In order to remove the broken male member 24 from the female member 26, the male member, illustrated as a stud, is first provided with a center bore 28 which has a diameter less than the diameter of the male member 24. The chisel-shaped end 18 of the working section 13 is inserted within the bore 28 and the tool is then driven into the bore 28 by the application of impact blows from a hammer to the end 14 thereof. The tapering top, bottom and side surfaces maintain the tool in alignment with the axis of the bore 28 as the tool is driven into the same. When the male member is a broken pipe section, the working section of the tool is driven directly into the central passage of the pipe section.

As shown in FIG. 6, the working section 13 of the tool is driven into the male member 24 until the top and bottom surfaces 16 and 17 are adjacent opposite portions 29 and 31 of the wall of the bore 28 so that the knifelike edges 22 and 23 are driven into the wall in positive engagement with the threaded male member 24. The maximum width of the tool across the working section 13 from the edge 22 to the edge 23 is smaller than the diameter of the threaded bore 27 in the female member 26.

After the working section 13 of the tool 10 is driven into the threaded male member 24 a Wrench or socket handle is attached to the non-circular handle section 12 of the tool. A force is applied to the wrench to rotate the tool about its longitudinal axis in a counterclockwise direction as shown by the arrow in FIG. 6 to back off the right hand threaded male member 24 from the female member 26. With the top and bottom surfaces 16 and 17 adjacent the knifelike edges 22 and 23 imbedded in the threaded male member the rotational force applied to the tool tangentially to the male member 24 is transmitted in a pair of substantially parallel planes which extend perpendicular to the axis of the male member 24. The tangential force applied to the male member 24 does not have a component which would destroy the positive engagement between the working section 13 of the tool and the male member 24 established by driving the tool into the center opening of the male member. In other Words, as the tool is turned it tends to screw into the bore of the male member 24.

The cross sectional dimensions and longitudinal lengths of the working section 13 of the tool 10 depend upon the size of the pipe or stud to be removed. In use, the mechanic is provided with a series or set of tools 10 which vary in size. The mechanic selects the proper size tool corresponding to the size of the center bore in the male member to be removed.

While there have been shown, described, and pointed out the fundamental novel features of the invention as applied to the preferred embodiment, it will be understood that various omissions, substitutions, changes in form, and details of the tool illustrated may be made by those skilled in the art without departing from the spirit of the invention. It is intended to be limited only as indicated by the scope of the following claim.

I claim:

A tool for removing broken threaded studs from threaded bores comprising: an elongated body having a handle section and an integral working section, said handle section being of uniform dimensions and regular in cross section, said working section having opposed surfaces defining a regular parallelogram in cross section, portions of the major surfaces of said working section contacting the work piece and forming the driving surfaces of the tool, said working section being of uniformly diminishing cross section with said surfaces tapering inwardly from said handle to the end of said tool, said parallelogram having major and minor sides and diagonals, the adjacent sides intersecting at the ends of said major diagonal thereby defining two cutting edges and the driving surfaces, and said Working section terminating at the end of said tool in a chisel point.

References Cited in the file of this patent UNITED STATES PATENTS 1,105,535 Roberts July 28, 1914 1,386,056 Groh Aug. 2, 1921 1,604,032 Ferrell Oct. 19, 1926 1,863,046 Githens et al. June 14, 1932 1,875,484 Nigra Sept. 6, 1932 2,244,824 Caminez June 10, 1941 

